let map = new Map([iterable])

let keyObj = {}
let keyFunc = function () { }
let keyString = 'a String'

map.set(keyString, "和键'a String'关联的值")
map.set(keyObj, '和键keyObj关联的值')
map.set(keyFunc, '和键keyFunc关联的值')

// map.delete(keyObj)
// map.clear()

// console.log(map.size)
// console.log(map.has(keyObj))

console.log(map.get(keyObj))

map.forEach((value, key) => {
    console.log(value, key)

    for (let [key, value] of map) {
        console.log(key, value)
        
    }
    for (let key of map.keys()) {
        console.log(key)
    }
    for (let value of map.values()) {
        console.log(value)
    }
    for (let [key, value] of map.entries()) {
        console.log(key,value)
    }
})


var a = 20
var b = 10
var c = 'JavaScript'
var str = 'My age is' + (a + b) + 'and I love ' + c
console.log(str)


var retailPrice = 20
var wholesalePrice = 16
var type = 'retail'
var showTxt = ''
if (type === 'retail') {
    showTxt+='您此次的购买单价是：'+retailPrice
} else {
    showTxt += '您此次的批发价是:'+wholesalePrice
}






let o = {
    name: 'xiaoming',
    age: 20
    }
    
    console.log(o.name)
    console.log(o.age) 
    console.log(o.from) 










